I was just showing that even a CC Phoenix 45 can be used with a 4S A123 2300 pack at up to over 600 watts and still be just fine. 600 watts on a 4S means I was pulling over 60 amps.
These were limited burst as the aircraft withan AUW of 47oz. with the 4S has more tahn 200 wats per pound which means if the nose is pointed striaght up and WPT is applied in a very brief time it gets very small.

My son flys an Eltrifly (Horizion ) Mini Edge 540 with a CC Phoenix 25 a 4S 2300 A123 pack and Parkflyer 480 motor and uses the built in BEC with 4 Hitec HS 55 servos and fly 3D / sport / pattern with it. I do not recomend using the built in BEC with over 3 cells but it can be done. We both fly Spektrum radios (DX7) and they do not drop out / reboot.

Charles